In recent years, along with improvement in performance and downsizing of imaging elements using solid state image sensors such as a CCD (Charge Coupled Device) image sensor or a CMOS(Complementary Metal Oxide Semiconductor) image sensor, portable phones and portable information terminals equipped with image pickup apparatuses are becoming widely used. Thus, imaging lenses to be built in these image pickup apparatuses are required to be further downsized and advanced in performance. As imaging lenses for such applications, there is proposed a five element imaging lens for the reason that it can have higher performance than a three element lens or a four element lens.
There is disclosed as the five element imaging lens an imaging lens constituted by, in order from an object side: a first lens having a positive refractive power, a second lens having a negative refractive power; a third lens having a positive refractive power; a fourth lens having a negative refractive power; and a fifth lens having negative refractive power (see Patent Document 1, for example).
In addition, there is disclosed an imaging lens, in order from an object side: a first lens having a negative refractive power; a second lens having a positive refractive power; a third lens having a negative refractive power; a fourth lens having a positive refractive power; and a fifth lens having negative refractive power (see Patent Document 2, for example).